This invention relates to the production of improved antimicrobial fabrics and articles made therefrom, which fabrics and articles do not lose the desirable attributes of comfort, soft hand, absorbency, better appearance which have heretofore been available only by utilization of naturally occurring articles. "Antimicrobial" is used herein to include both fungicidal and antibacterial agents, the latter functioning as either bacteriostatic or bactericidal agents. Much research has been conducted in this field with considerable development in the areas of clothing and intimate apparel. Efforts have been somewhat concentrated in the areas of deodorizing or inhibiting bacterial, fungal, or microbial growth in synthetic textile articles such as surgical gowns and masks, institutional textile products, and clothing items such as shirts, T-shirts, and athletic uniforms, etc. Inhibiting fungal growth serves to protect the fabric itself, while the inhibition of bacterial growth prevents odor, since odor is caused by the bacterial breakdown of organic matter. Therefore, both characteristics are desirable.
Many approaches have proved impractical or have demonstrated limited success. Two approaches are described in U.S. Pat. No. 3,922,723 and No. 3,296,000. Utilization of these teachings has demonstrated that the antimicrobial topical treatments to the yarns and/or fabrics is relatively shortlived. This fact is particularly true for articles of clothing the surfaces of which are subjected to mechanical abrasion during repeated cleaning and launderings. Each cleaning process removes a certain amount of the antimicrobial agent until the agent is dissipated and of no effectiveness.
Another approach to antimicrobial yarns and fabrics is disclosed in applicant's previous patent, U.S. Pat. No. 3,959,556, directed to a composite yarn construction showing a desirable level of antimicrobial activity. The yarn disclosed therein includes naturally occurring fibers intimately combined with a selected group of antimicrobially treated synthetic fibers. The results are characterized by the migration of the antimicrobial agent from within the intermolecular structure of the synthetic fibers onto the surface of and throughout the naturally occurring fibers, to impart antibacterial properties not only to the synthetic fibers but also to the naturally occurring fibers. A preferred embodiment of this yarn is a construction from synthetic polymeric fibers having an antimicrobial agent incorporated therein in an amount equalling at least 0.1% by weight of the polymeric resin, the antimicrobial agent selected from the group consisting of 2,4,4'-trichloro-2'-hydroxydiphenyl ether; 2,2'-methylenebis-(3,4,4'-trichlorophenol); and 2,2'-thiolis, 4,6-dichlorophenol. The chemical data describing the antimicrobial treatment of the synthetic fibers is fully described in applicant's aforementioned U.S. Pat. No. 3,959,556, the disclosure of which is hereby incorporated by reference in the present application.
The aforementioned earlier patent 3,959,556 requires intimate admixing of antimicrobially treated fibers and naturally occurring fibers in order to transfer the effect to the natural fibers. The present application is directed to achieving the same effect without such intimate admixing of fibers. This effect is achieved by constructing a "two-face" fabric, one of the faces formed at least in part by synthetic yarn which has been "treated" with an antimicrobial agent as described in the patent 3,959,556, the other of the faces comprising untreated yarn. As used herein "treated" with an antimicrobial agent includes the incorporation of the agent into the intermolecular structure of the resin so that it migrates to the surface thereof maintaining a relatively permanent treatment thereof. The "two-face" fabric may be a plated fabric with or without a tie yarn, it may be a carpet construction with a woven backing having other yarn tufted thereto, or other similar constructions in which yarns of one type are joined together to form a layer in one plane while yarns of another type are joined together to form a second layer in generally a second plane.
In one embodiment, the fabric formed according to the present invention is used to construct athletic sweatshirts having a face fabric and a backing fabric. The face fabric is formed of a 50% acrylic-50% cotton, antimicrobially untreated yarn; and the backing fabric is formed of a 100% acrylic, antimicrobially treated yarn. The interconnecting or tie yarn may be either fiber, preferably the same as in the face.
Experimentation with such a fabric structure has demonstrated the unexpected ability of the active antimicrobial agent to migrate all the way from a backing fabric to a face fabric. Although the two faces are not in intimate contact with each other due to the tie yarn in between, such a plated fabric structure has been found effective in not only the treated backing fabric, but also in the untreated face fabric.
Demonstration of the above unexpected capabilities of a treated fabric to protect an adjacent untreated fabric enables the production of articles of apparel and other manufacture with advantages theretofore unattainable. For example, in the aforementioned sweatshirt construction, it is not essential that the face fabric which normally forms the outside of the sweatshirt contain any antimicrobially treated, synthetic yarn. Rather a fabric formed of untreated, perhaps natural, fiber having a more pleasing appearance and feel (hand) and wearability can be used on the outside. The antimicrobially treated, synthetic yarn then can be used in the backing fabric alone. The antimicrobial agent will migrate from the backing fabric to the untreated facing fabric. Alternatively the synthetic, treated fabric might be in the face, while the backing fabric could utilize more comfortable natural yarns next to the skin. Other articles might use either alternative depending on the desired results.
Where in the past it has always been necessary that the antimicrobial fibers be intimately admixed with the non-antimicrobial fibers, as by blending, plying and the like, and the fabric formed therefrom necessarily in contact with the body of the wearer, it is now possible to alter that arrangement almost as desired. It is now possible that the treated and untreated fibers or fabrics can be only adjacent, not necessarily interlaced or intertwined, and they may even be tied together by an untreated yarn or fabric. This is also quite advantageous from an appearance standpoint. The visible face fabric need not have any synthetic yarns therein, but can have antimicrobial properties resulting from an invisible, treated backing fabric.
The ability of the one face having one antimicrobial properties to protect against microbial growth on the other is far more than other known approaches of treated yarns and/or fabrics have offered. Growth of mildew and odor forming bacteria has been significantly decreased as will be discussed in the example below.
A primary object of the present invention is the provision of a fabric construction wherein an antimicrobially treated fabric is formed in a "two-face" or layered relation with a non-antimicrobial, or untreated fabric, with the effect being that the untreated fabric receives the benefits of the antimicrobial agent in the treated fabric even where the two fabrics are not intimately joined. This objective has been realized with the antimicrobial properties of the combination exceeding expectations.
Other objects and a fuller understanding of the invention will become apparent upon reading the following detailed description of a preferred embodiment along with the accompanying drawings in which: